Non-powered seawater pumping system for reducing seawater intrusion, and apparatus and method for optimal design of well in the same system

A non-powered seawater pumping apparatus for reducing seawater intrusion in a land in which an aquifer with a seawater-fresh water boundary surface is formed, the apparatus comprising:

• a pumping pipe having two open end portions, a first end portion of the open end portions being positioned below a sea level and a second end portion being positioned below the seawater-fresh water boundary surface in the land;
• and
• a well having a cylindrical shape of which an upper portion is opened, the well being disposed to surround a lateral surface of a land-buried portion of the pumping pipe, which is buried in the land, so as to space away the land-buried portion of the pumping pipe from the land,
• wherein:
• the pumping pipe is filled with seawater,
• the well comprises a screen having a plurality of through holes formed along a circumference of the well at a lower end portion of the well,
• the seawater that flows into the well through the through holes is filled up to a groundwater level, and
• when a level of the seawater in the well is higher than the sea level, the non-powered seawater pumping apparatus performs non-powered pumping of the seawater in the pumping pipe to a sea,
• wherein:
• at least one of a location of the well, a screen height of the well, and a diameter of the pumping pipe is determined based on at least one of a target time ratio, a boundary reduction volume ratio, and a boundary reduction area ratio;
• the target time ratio is proportional to a ratio of a target boundary arriving time to a reduced target time;
• the boundary reduction volume ratio is proportional to a ratio of a volume affected by seawater after pumping to a volume affected by seawater prior to pumping;
• and
• the boundary reduction area ratio is proportional to a ratio of a reduced area of the boundary surface after pumping to an initial area of the boundary surface prior to pumping.